1. Field of the Invention
This invention relates to a cover apparatus for a manhole, pipe, or valve, and, more particularly, to a temporary cover for a manhole, pipe, or valve access opening utilizing a seal element that fits around the outer circumference of a depending side wall of the cover apparatus. The seal element provides a secure seal between the cover and the access opening. An externally flared side wall extends below the depending side wall to improve the seal between the seal element and the access opening by helping to restrain the seal element between the depending side wall and the access opening.
2. Description of the Prior Art
Water lines, sewer lines, and the like, and electrical wiring, etc., are typically buried under public rights of way, such as streets, alleys and easements. Access openings are spaced at intervals throughout the system of pipes. The access openings above normally open shut off valves are incorporated for the purpose of selectively isolating sections of the pipe in the event of a break or leak in the system.
The shut off valves are frequently buried several feet below the street. Access pipes or openings extend upwardly from the buried valves to the surface to provide a passage for a tool to selectively actuate the valve between its on and off positions. A mechanical cover assembly having a removable cover has traditionally been used to prevent debris from entering the access pipe. The cover assembly typically includes a cast iron cover with a mechanical locking apparatus to secure the cover to a concrete casting which supports the cover.
Drain and water lines are usually installed before the road or site grading begins. Manhole vault access openings to sewer systems are also placed in public rights of way, and are spaced at intervals throughout the system. Drainage gates are used to drain parking areas and other large surface areas. Drainage gates use slotted covers, and are also connected to the sewer system.
Municipalities usually bury their water and sewer main feeder pipes under public right of way, such as streets, alleys, and easements. Access opening elements are spaced at intervals throughout the pipe system. The access openings are used to isolate sections of the pipe in the event of a break or leak in the pipe system. Shutoff valves (not shown) are positioned adjacent to these access openings, to enable a worker to access a selected shutoff valve with a tool from the surface. Shutoff valves are typically installed several feet below ground. When these access openings are left uncovered, they tend to accumulate debris during the construction process, and pose a threat to people and vehicles in proximity to the access openings. Large flat steel plates (not shown) are sometimes used to cover access openings during construction. These plates are difficult to handle and position, and do not stop dirt, dust and other objects from entering the access opening beneath the steel plates, when the steel plates are not precisely aligned with the top of the access opening. Misaligned steel plates may form a safety hazard for vehicles passing over them, and do not stop vandals from removing the steel plates.
What is needed is a temporary cover that will easily conform to the rough and often unfinished top surface of the concrete manhole vault or on the top of a smaller diameter pipe which provides access to a shut off valve several feet below grade level. The temporary cover will stop dirt from being pushed into the sewer line or valve access pipe during grading or road construction, etc. Currently, large steel plates are placed over these manhole vaults, and are later removed when the final cast and ring setting work is complete. Steel plates provide a poor fit, and do not stop vandals from intruding into the pipes during construction.